Linear algebra: please solve q6 and 8 correctly and handwritten example 2 are also attached

Algebra & Trigonometry with Analytic Geometry
13th Edition
ISBN:9781133382119
Author:Swokowski
Publisher:Swokowski
Chapter9: Systems Of Equations And Inequalities
Section9.7: The Inverse Of A Matrix
Problem 32E
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Linear algebra: please solve q6 and 8 correctly and handwritten example 2 are also attached

HE
EXAMPLE 1
Solution
Therefore, S-¹AS has the form
S-¹AS =
0 0 0
and we have shown that if A has n linearly independent eigenvectors, then A is similar
to a diagonal matrix.
λ₁ 0
0
22
0
0
Now suppose that C-¹AC = D, where C is nonsingular and D is a diagonal matrix.
Let us write C and D in column form as
C = [C1, C₂, ..., C₁] and D= [d₁e₁, d₂e2, ..., dnen].
From C-¹AC = D, we obtain AC = CD, and we write both of these in column form as
AC = [AC₁, AC2, ..., ACn]
CD= [d₁ Ce₁, d₂Ce2,..., dn Cen].
But since Cek = Ck for k= 1, 2, . . . , n, we see that AC = CD implies
ACk = dk Ck, k = 1,2,..., n.
Since C is nonsingular, the vectors C₁, C2,..., Cn are linearly independent (and in
particular, no Ck is the zero vector). Thus the diagonal entries of D are the eigenvalues
of A, and the column vectors of C are a set of n linearly independent eigenvectors.
EXAMPLE 2
Note that the proof of Theorem 19 gives a procedure for diagonalizing an (n = n)
matrix A. That is, if A has n linearly independent eigenvectors u₁, U2, ..., un, then the
matrix S = [u₁, u₂, ..., u₂] will diagonalize A.
Solution
Show that A is diagonalizable by finding a matrix S such that S-¹AS = D:
5 -6
3 -4
Forming S = [u₁, u₂], we obtain
=
It is easy to verify that A has eigenvalues λ₁ = 2 and λ₂ = -1 with corresponding
eigenvectors
A =
--8---8
and u₂ =
0
0
23
5-6 -44]
-[21]
S =
2
Next, forming S-¹(AS), we obtain
S-¹ (AS) =
0
0
0
:
an
As a check on the calculations, we form S-¹AS. The matrix AS is given by
5 -6
2 1
AS = [] [] []
3 -4
1
−1 2
D¹0
4.7 Similarity Transformations and Diagonalization
S-1
=D;
[4][3][8]
- [ 20⁰
Hence A¹0 SD ¹0 S-¹ is given by
Use the result of Example 1 to calculate A¹0, where
5 -6
3 -4
4 10.
A =
A¹
=
0
(-1) ¹⁰
=
As was noted in Eq. (2), D¹0 = S-¹A¹0 S. Therefore, A ¹⁰ SD10 S-1. Now by
Example 1,
>]-[1024]
2047 -2046
1023-1022
2 0
0 -1
= D.
329
Sometimes complex arithmetic is necessary to diagonalize a real matrix.
Transcribed Image Text:HE EXAMPLE 1 Solution Therefore, S-¹AS has the form S-¹AS = 0 0 0 and we have shown that if A has n linearly independent eigenvectors, then A is similar to a diagonal matrix. λ₁ 0 0 22 0 0 Now suppose that C-¹AC = D, where C is nonsingular and D is a diagonal matrix. Let us write C and D in column form as C = [C1, C₂, ..., C₁] and D= [d₁e₁, d₂e2, ..., dnen]. From C-¹AC = D, we obtain AC = CD, and we write both of these in column form as AC = [AC₁, AC2, ..., ACn] CD= [d₁ Ce₁, d₂Ce2,..., dn Cen]. But since Cek = Ck for k= 1, 2, . . . , n, we see that AC = CD implies ACk = dk Ck, k = 1,2,..., n. Since C is nonsingular, the vectors C₁, C2,..., Cn are linearly independent (and in particular, no Ck is the zero vector). Thus the diagonal entries of D are the eigenvalues of A, and the column vectors of C are a set of n linearly independent eigenvectors. EXAMPLE 2 Note that the proof of Theorem 19 gives a procedure for diagonalizing an (n = n) matrix A. That is, if A has n linearly independent eigenvectors u₁, U2, ..., un, then the matrix S = [u₁, u₂, ..., u₂] will diagonalize A. Solution Show that A is diagonalizable by finding a matrix S such that S-¹AS = D: 5 -6 3 -4 Forming S = [u₁, u₂], we obtain = It is easy to verify that A has eigenvalues λ₁ = 2 and λ₂ = -1 with corresponding eigenvectors A = --8---8 and u₂ = 0 0 23 5-6 -44] -[21] S = 2 Next, forming S-¹(AS), we obtain S-¹ (AS) = 0 0 0 : an As a check on the calculations, we form S-¹AS. The matrix AS is given by 5 -6 2 1 AS = [] [] [] 3 -4 1 −1 2 D¹0 4.7 Similarity Transformations and Diagonalization S-1 =D; [4][3][8] - [ 20⁰ Hence A¹0 SD ¹0 S-¹ is given by Use the result of Example 1 to calculate A¹0, where 5 -6 3 -4 4 10. A = A¹ = 0 (-1) ¹⁰ = As was noted in Eq. (2), D¹0 = S-¹A¹0 S. Therefore, A ¹⁰ SD10 S-1. Now by Example 1, >]-[1024] 2047 -2046 1023-1022 2 0 0 -1 = D. 329 Sometimes complex arithmetic is necessary to diagonalize a real matrix.
In Exercises 1-12, determine whether the given matrix
A is diagonalizable. If A is diagonalizable, calculate A³
using the method of Example 2.
3. A =
5. A =
7. A =
8. A =
[
-3 2
-2 1
2]
3 -2 -4
8-7-16
-3 3 7
-1 -1 -4
-8-3-16
12
1 0
10 2
7
4. A =
4.7 Si
13
[8³]
01
6. A = [-17]
01
Transcribed Image Text:In Exercises 1-12, determine whether the given matrix A is diagonalizable. If A is diagonalizable, calculate A³ using the method of Example 2. 3. A = 5. A = 7. A = 8. A = [ -3 2 -2 1 2] 3 -2 -4 8-7-16 -3 3 7 -1 -1 -4 -8-3-16 12 1 0 10 2 7 4. A = 4.7 Si 13 [8³] 01 6. A = [-17] 01
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